This paper provides a comparative analysis of two contextual determinants of protest participation in 17 Western democracies at the beginning of the 1990's. The two determinants are the individual's organizational context and the national context of political and socioeconomic conditions. The organizational context is defined as the close context of political protest arising due to social interaction, while the national context is defined as the wide context, constituting of extra-individual factors. The relationship between the close context and political protest is specified by theories of mobilization, whereas in the case of the wide context modernization theories are used. Individual-level analysis of the effects of the close context reveals that protest participation increases with an individual's embeddedness in political organizations. This holds true not only for memberships in new but also in traditional political organizations. However, the organizational context does not contribute equally to all forms of protest. Its impact is stronger on legal than on illegal forms of protest. Concerning the wide context of political protest, evidence is provided by aggregate-level analysis that variations in the extent of legal protest between countries can be explained by different levels of political and socioeconomic modernity of societies. The more modern a society, the higher the extent of legal protest participation and the less legal protesters articulate demands for radical change to the societal order. To the contrary, the extent of illegal protest participation cannot be explained by a modernization approach. The research on the close and wide context of political protest indicates that the enlargement of the action repertory of citizens to include legal protest, is part of the modernization of politics.